The invention relates to a supporting device such as, for instance, a cushion comprising a space formed by a flexible envelope and filled with a plurality of elements, the elements in the space being movable relative to each other and each element consisting of a gas-filled, flexible and thin-walled covering of gastight design, so that the elements are deformable and accordingly provide the distribution of a pressure over the supporting device.
Such a supporting device is described in European patent 0200822. The gas-filled elements described in this European patent have dimensions of between 5 microns and 50 mm. A problem occurring with this supporting device is that if the supporting device is for instance used as a seat cushion, insufficient regard is paid to the fact that the pressure or force exerted by a human body on the supporting device is too slight to realize an optimum adaptation of the contents of the supporting device to the body contour. As a consequence, on the basis of insufficient form adaptation, the pressure distribution over the supporting device is not optimal, as a consequence of which such a supporting device, after long use, offers less comfort to a user and may even give rise to bodily complaints.
Apart from the supporting device described in European patent 200822, many supporting methods have meanwhile been conceived and marketed, based on the support by means of air and controlled by means of all types of pump systems, whether or not in combination with segmentation. These methods relate at least substantially to mattresses only.
The drawback of this is, in general, a reduction of pressure-distributing capacity. Besides, such supporting devices have the drawback that they usually have to be individually adjusted to the relevant user. In addition to becoming leaky, such a supporting device is rather liable to be damaged on account of the electric equipment that is typically used. Moreover, the problem of the instability and hence lack of comfort is still present and, furthermore, a vibrating pump may cause an additional discomfort. In particular within the medical care, the increase of the ageing population has resulted in a growing need for simple, lightweight, comfortable and high-quality cushions and mattresses and other supporting devices with a high degree of operational reliability. The need for operational reliability plays an extra great part in, in particular, the likewise growing home care. In addition, sitting occupies a greater and greater part of our lives, and in situations wherein people are sitting for a longer time (office, stadium, plane, car) there is also a need for a supporting device of the type described in the preamble which does not comprise the above drawbacks. Provided that it is designed in accordance with the invention, such a supporting device will provide a better support and, accordingly, more comfort than a supporting device consisting of foam or another nondynamic supporting medium.
The invention meets this need and has as a characteristic that the covering of a number of elements is manufactured from at least substantially nonelastic material, each of these elements being filled with the gas for 50-98 percent of its maximum volume and having a volume of from 10 cm3 to 100 cm3.
As, in accordance with the invention, the elements are filled with the gas for 50-98 percent of their maximum volume, it is provided that the elements can deform individually and thus provide an additional shape-adaptability of the supporting device under slight load. In addition, this degree of filling together with the volume taken up by the elements involves that the elements can move along one another relatively easily, also when the supporting device is loaded. It is thus provided that when the supporting device is loaded, the elements can reposition relative to each other relatively easily. With this, a supporting device obtains as it were an additional degree of freedom for reacting to a load. Moreover, it is provided that as a consequence of the repositioning of the various elements relative to each other, an optimum pressure distribution along and shape adaptation to the body contour of a user of the supporting device is realized.
In accordance with a specific embodiment, a lubricant is present in the envelope, between the elements, for facilitating a movement of the elements relative to each other caused by a load on the supporting device.
In accordance with another aspect of the invention, which provides a solution to the above-outlined problems, a supporting device of the type described in the preamble, there being further present in the space between the elements a lubricant for facilitating a redistribution of the elements in the space through relative movement in the envelope in reaction to a load on the supporting device, is further characterized in that in the space between the elements a free amount of gas is present, so that a minimum amount of lubricant is present, with the gas facilitating a form restoration of the supporting device after the removal of a load on the supporting device. More in particular, the supporting device comprises means for decreasing the amount of gas in the space in the case of a load on the supporting device and for increasing the amount of gas upon the removal of a load on the supporting device without involving a variation of the amount of lubricant in the supporting device.